1. Field of the Invention
The present invention relates to an existing pipe rehabilitation construction method that rehabilitates an existing pipe, such as a sewer pipe, by laying a rehabilitating pipe inside the existing pipe.
2. Description of the Prior Art
As an example of a conventional existing pipe rehabilitation construction method, a method is described in Japanese Examined Patent Application No. 55-43890 wherein a lining material comprising a tubular (bag shaped) flexible resin absorber impregnated with a liquid setting resin is supplied in a strip shaped, folded configuration. The lining material is then inserted inside the existing pipe and pressed against an inner circumferential surface of the existing pipe by the pressure of a fluid, such as water, so that it takes a tubular shape that is the same shape as the inner circumferential surface of the existing pipe. The setting resin is then hardened to provide a rehabilitating pipe for the existing pipe. Furthermore, if the diameter of the existing pipe is large, then a gap is created between the outer circumference of the rehabilitating pipe and the inner circumference of the existing pipe due to shrinkage when hardening the lining material; therefore, by filling that gap with filler and hardening the filler, the rehabilitating pipe, the filler, and the existing pipe are integrated as a compound pipe, thereby improving strength. Furthermore, there are also cases where, to improve strength, a gap of a prescribed dimension is secured in advance by preinstalling spacers on the inner circumferential surface of the existing pipe, and the gap is then filled with filler.
In addition, Japanese Laid Open Patent Application No. 2003-286742 describes a rehabilitation construction method wherein: a rehabilitating pipe is assembled and laid in the pipe longitudinal direction using segments. One segment is equivalent to a block obtained by partitioning a small rehabilitating pipe in the circumferential direction and the pipe longitudinal direction. The segments are coupled in the circumferential direction and the pipe longitudinal direction; and the gap between the outer circumference of that rehabilitating pipe and the inner circumference of the existing pipe is filled with a filler, which is then hardened, thereby integrating the rehabilitating pipe, the filler, and the existing pipe as a compound pipe.
Rehabilitating pipes comprising the above discussed lining material or segments are often laid so long as to extend from the opening of the portion that intersects with a manhole to the opening of the portion that intersects with the next manhole. After laying a rehabilitating pipe in that manner, it is necessary to prevent the leakage of filler by, prior to filling with the filler, sealing the gap (opening) between the outer circumference of the rehabilitating pipe and the inner circumference of the existing pipe. This sealing is also required to prevent infiltration of external ground water. In addition, if, for example, the rehabilitating pipe is laid such that it intersects a branch pipe, it is necessary to form a hole in the rehabilitating pipe that communicates with the branch pipe. Even in this case, it is necessary to prevent the leakage of filler and the infiltration of ground water by sealing the gap between the outer circumference of the rehabilitating pipe and the inner circumference of the existing pipe.
These gap openings have conventionally been sealed by plugging the gap opening with a sealing material comprising resin putty, mortar, and the like. Particularly in the case where the diameter of the existing pipe and the diameter of the rehabilitating pipe are large and the gap is therefore large, there is nevertheless a problem with this method in that it is difficult to perfectly seal the opening by completely plugging the entirety of the gap opening.
It is therefore an object of the present invention to provide an existing pipe rehabilitation method that, during the construction work of rehabilitating intersecting existing pipes, can perfectly seal the gap between the inner circumference of the existing pipe and the outer circumference of the rehabilitating pipe.